Kompetenzzentrum Automobil und Industrieelektronik GmbH

Villach, Austria

Kompetenzzentrum Automobil und Industrieelektronik GmbH

Villach, Austria

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Wheeler J.M.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Armstrong D.E.J.,University of Oxford | Heinz W.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Schwaiger R.,Karlsruhe Institute of Technology
Current Opinion in Solid State and Materials Science | Year: 2015

Nanoindentation measurement capabilities at elevated temperatures have developed considerably over the last two decades. Commercially available systems can now perform stable indentation testing at temperatures up to ∼800 °C with thermal drift levels similar to those present at room temperature. The thermal management and measurement techniques necessary to achieve this are discussed here, with particular emphasis on systems featuring independent heating of both the indenter and the sample. To enable measurements at temperatures where oxidation of the indenter and/or sample are a concern, vacuum nanoindentation techniques have also been developed. A natural extension of testing in vacuo is elevated temperature nanoindentation in situ in the scanning electron microscope, and the additional requirements for and benefits of this are discussed. Finally, several new emerging testing techniques are introduced: thermal cycling/fatigue, interfacial thermal resistance measurement and small scale transient plasticity measurements. © 2015 Elsevier Ltd.

Fellner K.,Polymer Competence Center Leoben | Antretter T.,University of Leoben | Fuchs P.F.,Polymer Competence Center Leoben | Pelisset T.,University of Leoben | Pelisset T.,Kompetenzzentrum Automobil und Industrieelektronik GmbH
Journal of Strain Analysis for Engineering Design | Year: 2016

In printed circuit boards, thin copper layers are used as current paths. During the thermal loading of printed circuit boards, stresses arise due to the different coefficients of thermal expansion of the used materials. To be able to model the mechanical behavior of printed circuit boards under cyclic thermal loads, cyclic mechanical tests of thin copper foils under changing tensile and compression loads at different temperatures were conducted. From these experiments, the isotropic and kinematic hardening parameters were determined serving as material input data for a nonlinear isotropic/kinematic hardening model in the finite element analysis-software Abaqus. The kinematic hardening parameters were fitted in an optimization process. The isotropic hardening variables were determined based on the stress versus plastic strain relationship that was constructed incrementally from the available individual cycles. The so-obtained curve was found to be not unique, but to depend on the loading situation. Hence, different approaches for strain range memorization were evaluated. Since these approaches were developed for modeling strain-controlled tests, whereas the experimental data were obtained in a force-controlled way, a phenomenological formulation was developed and applied. The results of curvature measurements during thermal cycling were used for model validation. The experimental results and the numerical predictions are in good agreement. © Institution of Mechanical Engineers. © IMechE 2015.

Lagger P.,Vienna University of Technology | Lagger P.,Infineon Technologies | Schiffmann A.,Infineon Technologies | Pobegen G.,Kompetenzzentrum Automobil und Industrieelektronik GmbH | And 2 more authors.
IEEE Electron Device Letters | Year: 2013

The very fast dynamics of threshold voltage drift (δVth) of GaN-based metal-insulator-semiconductor-HEMTs induced by forward gate bias stress is investigated with a simple oscilloscope based setup. We show that the logarithmic recovery time dependence of δVth, previously found for recovery times ranging from 10 ms up to 1 ms, extend even to the μs regime. Further, we observed an accumulation of δVth because of repetitive stress pulses of 100 ns. Consequences for device operation and reliability are discussed. © 2013 IEEE.

De Filippis S.,University of Naples Federico II | De Filippis S.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Kosel V.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Dibra D.,Infineon Technologies | And 4 more authors.
Microelectronics Reliability | Year: 2011

Electro-thermal simulators are useful tools for introducing design and technology improvements during the design process of power MOSFET transistors. They are also helpful to predict the device behavior when operating under extreme electrical and temperature conditions and thus to predict its thermal robustness. Such simulators have to correctly take into account interactions between electrical and thermal behavior. In this paper we propose a new method to perform electro-thermal simulations of power MOSFETs using ANSYS simulator. The electrical and the thermal problem are fully coupled and iteratively solved using the FEM method. By means of a test chip, simulations and comparison with measurement have been performed in order to validate the simulation approach. © 2011 Elsevier Ltd. All rights reserved.

Kosel V.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | De Filippis S.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | De Filippis S.,University of Naples Federico II | Chen L.,Infineon Technologies | And 2 more authors.
Microelectronics Reliability | Year: 2013

A simulation approach is presented which can be used to investigate electro-thermal behavior of power transistors in variety of operating conditions. The approach is discussed in detail and demonstrated using ANSYS simulator. The power transistor is considered as a distributed voltage controlled resistor consisting of many in parallel connected cells. Because every cell has individual gate- and drain-source voltage, 3-D effects depending on geometric configuration and used materials can be observed. This is shown on a simple power transistor model for three principal electrical operating points: below TCP (temperature compensated point), at TCP and above TCP. Additionally, a mix-mode operating point is showed. The simulation results show 3-D effect of current density distribution as a function of the operating points. The results showed very good agreement with the prediction from the theory and already published results achieved by 3-D modeling approaches. © 2012 Elsevier Ltd. All rights reserved.

Matoy K.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Matoy K.,Austrian Academy of Sciences | Matoy K.,University of Leoben | Schonherr H.,Infineon Technologies | And 3 more authors.
Thin Solid Films | Year: 2010

In this study miniaturized monolithic cantilevers of thermally grown silicon oxide and multi-layer cantilevers of plasma enhanced chemical vapor deposited silicon oxide and nitride were mechanically characterized. In order to determine the fracture stress as well as the fracture toughness, un-notched and focused ion beam pre-notched cantilevers were tested. While the thickness of the monolithic cantilevers was varied from 280 nm to 2380 nm, the individual sub-layer thickness of the multi-layer cantilevers was adjusted to 50 nm. Bending experiments reveal a small increase of the fracture stresses with decreasing cantilever thicknesses. For the multi-layer stacks the tensile stress at fracture slightly exceeds the strength values of the corresponding monolithic materials. Furthermore, it is demonstrated that the specimens pre-notched by focused ion beam do not show significant changes in fracture toughness with varying pre-notch size. This makes the applied test a reproducible technique to determine fracture toughness of brittle films. © 2010 Elsevier B.V. All rights reserved.

Wimmer A.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Leitner A.,Austrian Academy of Sciences | Detzel T.,Infineon Technologies | Robl W.,Infineon Technologies | And 4 more authors.
Acta Materialia | Year: 2014

In this study, the low-cycle fatigue properties (1-15,000 cycles) of electrodeposited Cu, which is frequently used as metallization in the semiconductor industry, is analyzed with respect to its microstructure. Freestanding Cu tensile samples 20 μm × 20 μm × 130 μm were fabricated by a lithographic process. The grain size of the samples was modified by using three different process conditions for electrochemical Cu deposition. All samples were subjected to cyclic tension-tension testing performed with a miniaturized stress-controlled stage in situ in a scanning electron microscope until failure occurred. The number of cycles sustained prior to failure depends on the accumulated creep strain and can be related to the failure strain in a tensile test. It will be shown that the microstructure influences the number of cycles to failure and the failure mode. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Philippi B.,Max Planck Institute Für Eisenforschung | Matoy K.,Infineon Technologies | Zechner J.,Kompetenzzentrum Automobil und Industrieelektronik GmbH | Kirchlechner C.,Max Planck Institute Für Eisenforschung | And 2 more authors.
Scripta Materialia | Year: 2016

Even though lead-free Sn-Ag-Cu based solder alloys are emerging as promising candidates to replace well-established but hazardous lead-containing solders, they suffer from limited knowledge about their mechanical performance. To ensure the high reliability demands in microelectronics, fracture properties need to be quantified with respect to crucial microstructural elements like Cu6Sn5 intermetallic compounds formed at common Cu metallization interfaces. While indentation fracture testing methods have shown varying fracture toughness values, micro-cantilever fracture testing is applied in this work on FIB-prepared single-crystalline Cu6Sn5 cantilevers to clarify on the microstructure-fracture relationship. © 2016 Elsevier B.V.

Heinz W.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Robl W.,Infineon Technologies | Dehm G.,Max Planck Institute Für Eisenforschung
Studies in Surface Science and Catalysis | Year: 2015

During a switch event in a power semiconductor device temperature changes of up to 300 K can occur in the Cu layer. Repeated switching operations causes cyclic thermal cycling which may finally lead to thermomechanical fatigue with severe microstructural changes. In this study, the influence of the starting microstructure and film thickness (600 nm and 5000 nm) on thermomechanical fatigue was investigated for epitaxial and polycrystalline Cu films for up to 1000 thermal cycles. Severe surface roughening and a texture change (crystal rotation) are detected during thermal cycling for the polycrystalline Cu films, while the epitaxial films maintain their microstructure. Controlling the initial microstructure of a Cu layer in a device exposed to cyclic thermomechanical straining is a route to delay surface damage. © 2014 Elsevier B.V. All rights reserved.

Wimmer A.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Heinz W.,Kompetenzzentrum Automobil und Industrie Elektronik GmbH | Detzel T.,Infineon Technologies | Robl W.,Infineon Technologies | And 5 more authors.
Acta Materialia | Year: 2015

Polycrystalline Cu samples 20 × 20 μm2 in size were cyclically bent inside a scanning electron microscope until fracture occurred. The microstructural changes were investigated by secondary electron imaging and electron backscatter diffraction. The in situ experiments revealed that, for the coarse-grained samples, it is not the external stress that dominates the cyclic deformation, but the local internal strength. This is in strong contrast to macroscopic bending samples, where deformation always happens near the fixed end of the bending beam and decreases constantly with increasing distance from the fixation. For micron-sized polycrystalline samples, the grain dimensions, dislocation density evolution and grain orientation (Taylor factor) can define the location of failure if the grain size and sample diameter become similar in size. A comparison with cyclic in situ tension-tension experiments (ratio of minimum stress to maximum stress R ≈ 0) reveals that cyclic bending experiments (R ≈ -1) undergo bulk-like fatigue deformation with extrusions/intrusions, in contrast to the experiments with R ≈ 0. Both the cyclic tension-tension and bending experiments can be described by a Basquin equation, although different mechanisms lead to failure of the samples. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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